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• How to correctly calculate address spaces?

  - by user337308

  Below is an example of a question given on my last test in a Computer Engineering course. Anyone mind explaining to me how to get the start/end addresses of each? I have listed the correct answers at the bottom... The MSP430F2410 device has an address space of 64 KB (the basic MSP430 architecture). Fill in the table below if we know the following. The first 16 bytes of the address space (starting at the address 0x0000) is reserved for special function registers (IE1, IE2, IFG1, IFG2, etc.), the next 240 bytes is reserved for 8-bit peripheral devices, and the next 256 bytes is reserved for 16-bit peripheral devices. The RAM memory capacity is 2 Kbytes and it starts at the address 0x1100. At the top of the address space is 56KB of flash memory reserved for code and interrupt vector table. What Start Address End Address Special Function Registers (16 bytes) 0x0000 0x000F 8-bit peripheral devices (240 bytes) 0x0010 0x00FF 16-bit peripheral devices (256 bytes) 0x0100 0x01FF RAM memory (2 Kbytes) 0x1100 0x18FF Flash Memory (56 Kbytes) 0x2000 0xFFFF

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• How to get physical memory in bash

  - by Neuquino

  I need to assign the RAM in bytes to a variable in bash, has anyone know how to do it? Thanks in advance

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• iPhone and Vertex Buffer Objects

  - by dancer

  I've just started playing around with opengl es on the iphone the past couple of weeks and i'm looking at refactoring some of my code to use Vertex Buffer Objects(VBO). Before I do though I would like to make sure it'll be worth it. The problem is that afaik the only reason you create VBO's is to shift a chunk of data onto the graphics card so that it doesn't need to be retrieved from system ram when it's used. The iPhone however does not have any dedicated ram that I'm aware of so i'm struggling to see why I would benefit at all from using VBO's. I have seen talk around the internet with conflicting opinions and apple certainly want dev's to use it so there's probably still a reason to use them but just wanted to see if anyone on SO had an opinion to add.

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• Optimising speeds in HDF5 using Pytables

  - by Sree Aurovindh

  The problem is with respect to the writing speed of the computer (10 * 32 bit machine) and the postgresql query performance.I will explain the scenario in detail. I have data about 80 Gb (along with approprite database indexes in place). I am trying to read it from Postgresql database and writing it into HDF5 using Pytables.I have 1 table and 5 variable arrays in one hdf5 file.The implementation of Hdf5 is not multithreaded or enabled for symmetric multi processing.I have rented about 10 computers for a day and trying to write them inorder to speed up my data handling. As for as the postgresql table is concerned the overall record size is 140 million and I have 5 primary- foreign key referring tables.I am not using joins as it is not scalable So for a single lookup i do 6 lookup without joins and write them into hdf5 format. For each lookup i do 6 inserts into each of the table and its corresponding arrays. The queries are really simple select * from x.train where tr_id=1 (primary key & indexed) select q_t from x.qt where q_id=2 (non-primary key but indexed) (similarly five queries) Each computer writes two hdf5 files and hence the total count comes around 20 files. Some Calculations and statistics: Total number of records : 14,37,00,000 Total number of records per file : 143700000/20 =71,85,000 The total number of records in each file : 71,85,000 * 5 = 3,59,25,000 Current Postgresql database config : My current Machine : 8GB RAM with i7 2nd generation Processor. I made changes to the following to postgresql configuration file : shared_buffers : 2 GB effective_cache_size : 4 GB Note on current performance: I have run it for about ten hours and the performance is as follows: The total number of records written for each file is about 6,21,000 * 5 = 31,05,000 The bottle neck is that i can only rent it for 10 hours per day (overnight) and if it processes in this speed it will take about 11 days which is too high for my experiments. Please suggest me on how to improve. Questions: 1. Should i use Symmetric multi processing on those desktops(it has 2 cores with about 2 GB of RAM).In that case what is suggested or prefereable? 2. If i change my postgresql configuration file and increase the RAM will it enhance my process. 3. Should i use multi threading.. In that case any links or pointers would be of great help Thanks Sree aurovindh V

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• Performance problem Loading Dataset inside a virtual.

  - by ShaneH

  Host Configuration: HP EliteBook 8530w 4G Ram Win7 Ultimate 64Bit RC SQL Server 2005 64bit Developer Edition Virtual: Windows Virtual PC 1G Ram allocated Integration Services installed Windows XP 64bit Up to date service packs and .Net framework through 3.5 SP1 Sharing the Gigabit network adapter of the Host I have a simple .Net console application which loads a dataset of approximately 37K rows. Running the application on the host executes in approximately 4 seconds. Running inside the virtual takes 729 seconds. The size of the application grows to about 65Mb when the dataset is finished loading, no calculated columns or event handlers are attached. [edit] I changed the virtual to use a loopback adapter to communicate with the host and performance is now on par with running on hardware. Any ideas as to why it would going over the network adapter be almost 200x longer? TraceRt shows that the connection is only one hop. Thanks, Shane Holder

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• .net - how to connect windows service with systray application

  - by razor

  I have a windows service that do something periodically. on user account runs systray application (written in C#) that communicate with windows service (thru .net remoting) and shows a status and some option to users. Everything works well beside that systray app uses 20-30MB of RAM ! it have to work in terminal environment, when 50 users login, only systray apps take 1GB of RAM ! and i don't have to add, that's wrong :) Is it possible to write .net systray application that will be small ? (1-2MB max?) or should I write it in c/c++? then, what kind of communication should I use between windows service (written in C#) and systray app ?

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• Does Django tests run slower on the mac compared to linux?

  - by Thierry Lam

  I'm currently developing my Django projects on both: Mac OS X 10.5, 32 bit Ubuntu Server 9.10 64 bits (1 CPU, 512MB RAM) Both of the above OS are using: Python 2.6.4 Django 1.1.1 MySQL 5.1 Running 12 tests for one of my application take: Mac: 57.513s Linux: 30.935s EDIT: Mac Hardware Spec: MacBook Pro 2.2 GHz Intel Core 2 Duo 3GB RAM I'm running the Ubuntu OS on the same mac above through VMware Fusion 2.0.6. You might argue that Ubuntu Server 64 bits is faster but I have observed a similar speed difference on Ubuntu 8.10 32 bits desktop edition. Even if I turn off my linux VM and other mac applications, I still experience the slowness. Has anyone else experienced this Django test speed difference across those two OS?

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• What performance indicators can I use to convince management that I need my development PC upgraded?

  - by Aaron Daniels

  At work, my PC is slow. I feel that I can be way more productive if I just wasn't waiting for Visual Studio and everything else to respond. My PC isn't bad (dual-core, 3GB of RAM), but there is a lot of corporate software and whatnot to slow everything down and sometimes lock it up. Now, some developers have begun getting Windows 7 machines with 8 GB of RAM. Of course, I start salivating at this. However, I was told that I "had to justify" why I should get a new machine. I can think of a lot of different things, but I am curious as to what every one else on SO would have to say. NOTE: Ideally, these reasons should be specifically related to .NET development in Visual Studio on a Windows machine. This isn't a "how can I make my machine faster" question.

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• Why does C++ linking use virtually no CPU?

  - by John

  On a native C++ project, linking right now can take a minute or two, yet during this time CPU drops from 100% during compilation to virtually zero. Does this mean linking is primarily a disk activity? If so, is this the main area an SSD would make big changes? But, why aren't all my OBJ files (or as many as possible) kept in RAM after compilation to avoid this? With 4Gb of RAM I should be able to save a lot of disk access and make it CPU-bound again, no?

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• What happens when a computer program runs?

  - by gaijinco

  I know the general theory but I can't fit in the details. I know that a program resides in the secondary memory of a computer. Once the program begins execution it is entirely copied to the RAM. Then the processor retrive a few instructions (it depends on the size of the bus) at a time, puts them in registers and executes them. I also know that a computer program uses two kinds of memory: stack and heap, which are also part of the primary memory of the computer. The stack is used for non-dynamic memory, and the heap for dynamic memory (for example, everything related to the new operator in C++) What I can't understand is how those two things connect. At what point is the stack used for the execution of the instructions? Instructions go from the RAM, to the stack, to the registers?

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• windows fails to allocate the amount of free physical memory returned by GlobalMemoryStatusEx

  - by avi

  hello! what i'm trying to do is get the free amount of physical memory allocate it and than manage it ( resizing it or delete it ) depending on what further calls to GlobalMemoryStatusEx return. and the problem : it works on 2 PCs with win 7 x64 one with 2G Ram ( on witch i was able to allocate like 1.3 GB) , the other has one 1GB RAM (max alloc was 630 MB). it fails on the third one with 3GB of ramm. I can't find the problem. !! i tried google!! any solution?

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• Why does C++ linking use virtually no CPU? (updated)

  - by John

  On a native C++ project, linking right now can take a minute or two, yet during this time CPU drops from 100% during compilation to virtually zero. Does this mean linking is primarily a disk activity? If so, is this the main area an SSD would make big changes? But, why aren't all my OBJ files (or as many as possible) kept in RAM after compilation to avoid this? With 4Gb of RAM I should be able to save a lot of disk access and make it CPU-bound again, no? update: so the obvious follow-up is, can VC++ compiler and linker talk together better to streamline things and keep OBJ files in memory, similar to how Delphi does?

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• scikit learn extratreeclassifier hanging

  - by denson

  I'm running the scikit learn on some rather large training datasets ~1,600,000,000 rows with ~500 features. The platform is Ubuntu server 14.04, the hardware has 100gb of ram and 20 CPU cores. The test datasets are about half as many rows. I set n_jobs = 10, and am forest_size = 3*number_of_features so about 1700 trees. If I reduce the number of features to about 350 it works fine but never completes the training phase with the full feature set of 500+. The process is still executing and using up about 20gb of ram but is using 0% of CPU. I have also successfully completed on datasets with ~400,000 rows but twice as many features which completes after only about 1 hour. I am being careful to delete any arrays/objects that are not in use. Does anyone have any ideas I might try?

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• Exchange Server 2007 Setup

  - by AlamedaDad

  Hi, I'm working on a upgrade to Exchange 2007 and I wanted to get some advise on hardware choices. We currently have an Exchange 2003 STD server with 400 users split between 6 AD Sites, that is housed on a single server. We need to move to a redundant, fault tolerant system to support our users. I'm planning on installing 2 Dell 1950 servers with W2k8-std to act as CAS and Hub servers, with NLB to allow abstraction of the actual server name to the users. There won't be an edge system since we have a Barracuda box already that will handle in/out spam/virus filtering. Backend I'm planning on 2 mailbox servers which will be Dell 2950s with 16GB RAM, 2 either dual-core or quad-core CPUs and 6 300GB SAS drives in some RAID config. These systems will be clustered using W2k8 Ent clustering and running CCR in Exchange. My questions are as follows: Is 16GB enough RAM for serving that many mailboxes along with the windows clustering and ccr? I'm trying to figure out disk layouts and I'm unsure of whether to use all local disk or some local and some SAN, via an OpenFiler iSCSI server. The SAN would be a Dell 2850 with 6 - 300GB SCSI drives and a PERC controller to slice as I want, with 8GB RAM. Option 1: 2 drives, RAID 1 - OS 2 drives, RAID 1 - Logs 2 drives, RAID 1 - Mail stores Option 2: 2 drives, RAID 1 - OS and logs 4 drives, RAID 5 - Mail Stores and scratch space for eseutil. Option 3: 2 drives, RAID 1 - OS 2 drives, RAID 1 - Logs 2 drives, RAID 0 - scratch space ~300GB iSCSI volume for mail stores Option 4: 2 drives, RAID 1 - OS 4 drives, RAID 5 - scratch space ~300GB iSCSI volume for mail stores ~300GB iSCSI volume for logs I have 2 sockets for CPUs and need to chose between dual and quad cores. The dual core have faster clocks but less cache and I'm thinking older architecture. Am I better off with more cores and cache while sacraficing clock speed? I am planning on adding the new E2K7 cluster to the E2K3 server and then move each mailbox over, all at once, then remove the old server. This seems more complicated than simply getting rid of the 2003 server and then adding the 2007 cluster and restoring the mailboxes using PowerControls or exmerge. The migration option lets me do this on my time, where a cutover means it all needs to work at once. If I go with the cutover method, how can I prebuild the servers and add them to the domain right after removing the 2003 server, or can't I? I think the answer is no and the migration is my only real option if I want to prebuild. I need to also migrate about 30GB of Public Folders. Is there anything special about this, other than specifying in the E2K7 install that I want older Outlook clients and PF's setup? I guess I could even keep the E2K3 server to host just the PFs? Lastly, if I have a mix of Outlook 200, 2003 and 2007 what do I need to do to make sure they all have access to the GAL and OAB? At time of cutover, we'll be at like 90% 2007, but we will have some older stuff around. My plan is to use Outlook Anywhere on laptops that are used outside the physical network. Are there any gotchas involved in that? I'm even thinking about using is for all Outlook clients, does anyone do that? The reason I'm considering it is that our WAN is really VPN tunnels over internet connections, so not a fully messhed, stable WAN. Thank you all very much for the assistance in advance and I look forward to discussion of these points! Regards...Michael

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• PC: Quick Freeze, then BSOD, then forced reboot, then freezes again

  - by cr0z3r

  Lately I have been experiencing a weird issue. My PC will hang for a second and then BSOD - it stays there, so I have to reboot. Once Windows starts again and I'm logged in, after 1-10min it freezes again, this time without BSOD. RECAP: 1 second freeze BSOD, hangs there I have to force-reboot Once PC rebooted, I log back into Windows second freeze between a 1-10min range, no BSOD (alternatively, I get a freeze with a constant sound/noise, no BSOD) I contacted my PC provider, who told me my graphics-card might be flawed (Quadro 4000), so I used a Quadro 2000 that they lend me. The issue still occurred. The issue now seemed to belong to a flawed RAM module. Following my provider's steps, I removed all but the first from the left column and kept using my PC for a week or so without any issues. I then added the bottom-right module, and so on, until all modules were back inside - I had no problems. Now it seemed that a simple take-out-put-back-in of the RAM modules had fixed the issue. However, after a few months, the issue was back. I redid all the RAM-swapping I had done before, and concluded that the lower-right module was flawed. My provider changed it for another, and everything was great until now. My PC froze again for barely a second, hanged on a BSOD, I rebooted it, logged-in to Windows to get a freeze (without BSOD or reboot) 40 seconds later. Something worth noting, is that every time I reboot after the BSOD, it is something within Chrome that freezes my PC (e.g. this time I clicked the "restore" button as Chrome mentioned it had exited unexpectedly - from the previous freeze obviously - and it instantly froze). Finally, the Event Viewer lists 2 critical events in the past hour as "ID: 41, Type: Kernel-Power". PC-Specs: http://i.imgur.com/VZpbr.jpg Previous Dump-files: https://dl.dropbox.com/u/716600/DumpFiles_08_2012.zip I would like to thank anybody in advance for your help. You're great. UPDATE 1: I realized that I did not mention an awkward fact about this issue. After I have gotten the 1-sec freeze followed by a BSOD, after I rebooted because the BSOD hanged, and after I logged back in to get another (this time, eternal) freeze and rebooted once again, the PC does not boot back up. The power-light is on, but my monitor says "no signal", as if the PC wouldn't really be turned on. This truly seems a like a power-related issue, doesn't it? UPDATE 2: I just got a freeze, but without BSOD. My screen froze (while on Chrome, which is starting to seem suspicious to me) with an ongoing sound/noise. I had to force-reboot my PC. I would say this is a graphics-card issue, but this issue also happened when I was using the Quadro 2000 from my provider. UPDATE 3: I just got a BSOD while trying to render something (quite heavy, actually) in 3ds Max 2012. I left the BSOD "running", as it said it was writing dump files to disk. However, the percentage number stayed at 0, so after 15 minutes I force-rebooted. I then used the software WhoCrashed (thank you Dave) which reported the following from the C:\Windows\Memory.dmp file: On Thu 22.11.2012 22:13:45 GMT your computer crashed crash dump file: C:\Windows\memory.dmp uptime: 01:05:27 This was probably caused by the following module: Unknown () Bugcheck code: 0x124 (0x0, 0xFFFFFA80275AC028, 0xF200001F, 0x100B2) Error: WHEA_UNCORRECTABLE_ERROR Bug check description: This bug check indicates that a fatal hardware error has occurred. This bug check uses the error data that is provided by the Windows Hardware Error Architecture (WHEA). This is likely to be caused by a hardware problem problem. This problem might be caused by a thermal issue. A third party driver was identified as the probable root cause of this system error. It is suggested you look for an update for the following driver: Unknown . Google query: Unknown WHEA_UNCORRECTABLE_ERROR

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• Strange Upload Problem on Hyper-V

  - by Ring0

  Hi, This one is driving me totally nuts. I have being trying to upload a file to www.virustotal.com (its a harmless exe I have since found out - DiskWipe.exe from diskwipe.org). Using IE8. From Win 7 and Win 2008 R2 Datacenter (which I select to boot from vhd's) onto my main machine hardware, and also on another Win 7 PC elsewhere on my network, when I upload the file to virustotal.com it works perfectly. So, using my native NIC's everything is fine. Using another machine also perfect. Right. OK, from my boot menu the default is my main development machine - the one I'm typing on now. This runs on the metal and has Hyper-V role and I have some guests. All guests are not running. Amazingly, from my console (root partition to be exact) or any guest OS 2003 /XP / 2008 R2 etc. My upload to virustotal.com slows at 32% then HANGS at 38.something% & never finishes!! Here is the kicker. I have another box (my main server) running Hyper-V on the metal and three live guests. Identical H/W to my main dev machine in another room. (Except OS is Datacenter - Mine is Enterprise). If I try and upload from its bare metal console or any guest this file to virustotal.com using IE8 it stops exactly in the same place!! As for "steps I have tried etc." are kind-of blown out of the water as my server box is doing the precise same thing as the machine in my room here. OK, comonalities: Mobo: Gigabyte GA-X58-UD5, 12GB Kingston RAM, Corei7 920 4 cores hyperthreading = 8 & Realtek RTL8168D/8111D Family PCI-E Gigabit Ethernet NIC's. All 3 machines have this same motherboard - revision F11 Bios, all have 12GB RAM, all have the Realtek Nic's. All x64 by the way as I mentioned before I have a Win 7 box also with the UD5 m/Board, 12 GB RAM - bit of an overkill. :-) All these machines when NOT running Hyper-V can upload this file. Perhaps you may like to try it on a Hyepr-v (2008 R2) yourselves with IE8 and the desktop experience is on. See if it works or fails for you. Root OS or any guest. So, looking like its the NIC + Hyper-V = Cannot upload this file (any file I must add.) Realtek Nic is Ver 7.002.1125.2008. Using IE8 I see in the nic settings there are the usual parameters for Jumbo frames / Checksum offloading etc. several others. Should I fiddle with these? I ran Netmon 3.3 in a guest and the TCP session halted as the upload failed. I suppose I could study that further. I dont have Netmon on the root partition machine (yet)! All OS's fully patched - including todays defender files. My box running Office 2007 - but identical server in another room is not. Also, if I fire up a VPN to a distant client and do the upload it works! Of course its a different network path. Suggestions welcome please. If I left out anything important - please yell at me. Many Thanks,

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• Problem with kickstart

  - by user70523

  Hi, I created a kickstart file ks.cfg and then I have put that in the bootable disk*(Ubuntu 10.04)* and then added the following line to the isolinux.cfg linux ks=ks.cfg and have not removed any other lines from the isoconfig.cfg file and then while installing the installation is not automated,again it is asking for language and all. If i removed include menu.cfg or any other line from isolinux.cfg i am getting a boot error. What should i do now to automate the installation.Where should i add the boot parameters so that installation will start from the ks.cfg . Thanks and Regards Ravi Kumar

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• How to stop Apache from crashing my entire server?

  - by CyberShadow

  I maintain a Gentoo server with a few services, including Apache. It's fairly low-end (2GB of RAM and a low-end CPU with 2 cores). My problem is that, despite my best efforts, an over-loaded Apache crashes the entire server. In fact, at this point I'm close to being convinced that Linux is a horrible operating system that isn't worth anyone's time looking for stability under load. Things I tried: Adjusting oom_adj for the root Apache process (and thus all its children). That had close to no effect. When Apache was overloaded it would bring the system to a grind, as the system paged out everything else before it got to kill anything. Turning off swap. Didn't help, it would unload memory paged to binaries of processes and other files on /, thus causing the same effect. Putting it in a memory-limited cgroup (limited to 512 MB of RAM, 1/4th of the total). This "worked", at least in my own stress tests - except the server keeps crashing under load (basically stalling all other processes, inaccessible via SSH, etc.) Running it with idle I/O priority. This wasn't a very good idea in the end, because it just caused the system load to climb indefinitely (into the thousands) with almost no visible effect - until you tried to access an unbuffered part of the disk. This caused the task to freeze. (So much for good I/O scheduling, eh?) Limiting the number of concurrent connections to Apache. Setting the number too low caused web sites to become unresponsive due to most slots being occupied with long requests (file downloads). I tried various Apache MPMs without much success (prefork, event, itk). Switching from prefork/event+php-cgi+suphp to itk+mod_php. This improved performance, but didn't solve the actual problem. Switching I/O schedulers (cfq to deadline). Just to stress this out: I don't care if Apache itself goes down under load, I just want the rest of my system to remain stable. Of course, having Apache recover quickly after a brief period of intensive load would be great to have, but one step at a time. Right now I am mostly dumbfounded by how can humanity, in this day and age, design an operating system where such a seemingly simple task (don't allow one system component to crash the entire system) seems practically impossible - or at least, very hard to do. Please don't suggest things like VMs or "BUY MORE RAM". Some more information gathered with a friend's help: The processes hang when the cgroup oom killer is invoked. Here's the call trace: [<ffffffff8104b94b>] ? prepare_to_wait+0x70/0x7b [<ffffffff810a9c73>] mem_cgroup_handle_oom+0xdf/0x180 [<ffffffff810a9559>] ? memcg_oom_wake_function+0x0/0x6d [<ffffffff810aa041>] __mem_cgroup_try_charge+0x32d/0x478 [<ffffffff810aac67>] mem_cgroup_charge_common+0x48/0x73 [<ffffffff81081c98>] ? __lru_cache_add+0x60/0x62 [<ffffffff810aadc3>] mem_cgroup_newpage_charge+0x3b/0x4a [<ffffffff8108ec38>] handle_mm_fault+0x305/0x8cf [<ffffffff813c6276>] ? schedule+0x6ae/0x6fb [<ffffffff8101f568>] do_page_fault+0x214/0x22b [<ffffffff813c7e1f>] page_fault+0x1f/0x30 At this point, the apache memory cgroup is practically deadlocked, and burning CPU in syscalls (all with the above call trace). This seems like a problem in the cgroup implementation...

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• Hardware recommendations / parts list for a modern, quiet ZFS NAS box - 2011-Feb edition [closed]

  - by dandv

  I want to build some really reliable storage for my data, and it seems that ZFS is the only filesystem at the moment that does live checksumming. That rules out DroboPro, so I'm looking to building a quiet ZFS NAS that would start with 4 2TB or larger hard drives. I'd like this system to be very reliable and relatively future-proof for 2-3 years, so I'm willing to invest some $$$ and buy higher end components. I did see questions here and on other forums about low-cost servers, but I'm not looking for those. I'd be super happy to go for an off-the-shelf solution, but I haven't found one that's quiet. I started doing the research (summarized on my wiki), but I realized that it just gets too complicated for what I know as a software dude, and I'm entering the analysis paralysis area. At this point, I'm basically looking for a parts list for a configuration that will work (and is modern), and I know there are folks around here who are way more competent than me. I've built computers and am comfortable assembling one and messing with *nix; I can follow guides; I just want to end the decision process for the hardware and software configuration. What I've researched so far (not that these are very modern components): Case: I think I've settled on the Antec Twelve Hundred case because it cools well, is quiet, and simply has 12 bays that allow elastic mounting. The SilverStone Raven is its counter-candidate, but I find its construction quite odd. For the PSU, I'm torn between Antec CP-850 and Nexus RX-8500, but I did this research more than a year ago. The Nexus has a very uniform power profile, and I'd rather not have the Antec spin up and down based on load. On the other hand, I'm not sure how often my file server will draw more than 400W under use. For the hard drives, I've read that WD Black drives are actually WD RE3 with a software setting changed. I'd also like to buy different drive types, not just 4 WDs. Recommendations? Right now I have a 2TB Hitachi Deskstar 7K300. For the motherboard, CPU and RAM I have no idea, other than the RAM must be ECC. I already asked a question here about ECC RAM, but I was misguided and was looking for a motherboard that would support USB 3.0 as well. I've learned to go with eSATA, or worry about USB later. Then there's the (liquid) cooling, Wi-Fi card, and FreeBSD vs. OpenSolaris Express. Lastly, I'm wondering if I can make this PC into a media server by adding a Blu-ray drive and a good sound card. But support for Blu-Ray is spotty on Linux, and I don't know if Windows 7 on VirtualBox would get sufficient hardware access to output HDMI or SPDIFF signals. (Running OpenSolaris virtualized is not an option because of the reliability risk.) Then there are HDCP concerns. Suggestions on that would be appreciated as well, but I don't want us to get sidetracked. A specific shopping list on the core components would be great, so I can start ordering, and in the meantime educate myself with regards to the other issues. Finally, I think this could become a great FAQ for those technically inclined to build their own ZFS server, but confused by the dizzying array of options out there, and I promise to compile the results and share my experience building and benchmarking the server.

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• Symantec Protection Suite and System Recovery 2011 Desktop Edition

  - by rihatum

  I am re-posting this as my previous question was being treated as if I am "Shopping or seeking Product Recommendations" even though I was NOT - BTW they have deleted my comments too which were not offensive in nature. anyway - I have re-phrased some parts of my question and I hope SF Admins "Do Not Modify / Edit" this one - will be most grateful for that. I have a lot of respect for the People who visit this SITE and help others ! Just To clarify : Just to go by SF rules - I am not seeking someone to Design this solution, I am simply seeking real world examples, experiences, technical expert opinions / suggestions, any tips or tricks they may have or any problems they may have faced while doing something similar above with these products. I am also not asking for Capacity Planning for Storage, We have done some research and I am seeking Expert Assurance / Suggestions. We (our company) are planning to deploy Symantec Endpoint Protection and Symantec Desktop Recovery 2011 Desktop Edition to our 3000 - 4000 workstations (Windows7 32 and 64) with a few 100s with Windows XP 32/64 Bit. I have read the implementation guide for SEP and have read tech-notes for Desktop Recovery 2011. Our team have planned to deploy this as follows : 1 x dedicated SQL 2008R2 for Symantec Endpoint Protection (Instead of using the Embedded Database) 1 x Dedicated SQL 2008R2 for Symantec Desktop Recovery 2011 (Instead of using the Embedded Database) 1 x Dedicated W2K8 R2 Box for the SEPM (Symantec Endpoint Protection Manager - Mgmt. APP) 1 x Dedicated W2K8 R2 Box for the Symantec Desktop Recovery 2011 Management Application Agent Deployment : As per Symantec Documentation for both of the above, an agent can be pushed via the Mgmt. Application (provided no firewalls are blocking ports required etc. - we have Windows firewall disabled already). Server Hardware : Per SQL Server : 16GB RAM + SAS DISKS + Dual XEON, RAID-10 for the SQL DB or I can always mount a LUN from our existing Hitachi or EMC SAN. SEPM Server : 16GB RAM + SAS DISKS + DUAL XEON System Recovery MGMT SERVER : 16GB RAM + SAS DISKS + DUAL XEON Above is the initial plan we have for 3000 - 4000 client workstation (Windows) Now my Questions :-) a) If we had these users distributed amongst two sites with AD DC / GC in each site, How would I restrict SEPM and Desktop Mgmt. solution to only check for users in their respective site ? b) At present all users are under one building but we are going to move some dept. to a new location (with dedicated connectivity), How would we control which SEPM / MGMT Server is responsible for which site ? c) We have netbackup in our environment backing up other servers, I am planning to protect these 4 (2 x SQL, 1 x SEPM, 1 x System Recovery Mgmt. Server) via netbackup or I can use System recovery 2011 server edition on all 4 of these boxes as well. (License is not an issue as we have the complete symantec portfolio included in our license). d) Now - Saving Desktop backups - What strategies have you implemented ? Any best practice recommendation for a large user base ? I was thinking to either mount a LUN from our Hitachi SAN on the Symantec Recovery Server itself or backup to the users hard drive locally and then copy it over to a network location ? Suggestions welcome :-) If you have anything to add / correct - that will be really helpful before diving into the actual implementation phase. Will be most grateful with your suggestions, recommendations and corrections with above - Many Thanks !

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• Clarification On Write-Caching Policy, Its Underlying Options And How It Applies To Hard Drives And Solid-State Drives

  - by Boris_yo

  In last week after doing more research on subject matter, I have been wondering about what I have been neglecting all those years to understand write-caching policy, always leaving it on default setting. Write-caching policy improves writing performance and consists of write-back caching and write-cache buffer flushing. This is how I understand all the above, but correct me if I erred somewhere: Write-through cache / Write-through caching itself is not a part of write caching policy per se and it's when data is written to both cache and storage device so if Windows will need that data later again, it is retrieved from cache and not from storage device which means only improved read performance as there is no need for waiting for storage device to read required data again. Since data is still written to storage device, write performance isn't improved and represents no risk of data loss or corruption in case of power failure or system crash while only data in cache gets lost. This option seems to be enabled by default and is recommended for removable devices with no need to use function of "Safely Remove Hardware" on user's part. Write-back caching is similar to above but without writing data to storage device, periodically releasing data from cache and writing to storage device when it is idle. In my opinion this option improves both read and write performance but represents risk if power failure or system crash occurs with the outcome of not only losing data eventually to be written to storage device, but causing file inconsistencies or corrupted file system. Write-back caching cannot be enabled together with write-through caching and it is not recommended to be enabled if no backup power supply is availabe. Write-cache buffer flushing I reckon is similar to write-back caching but enables immediate release and writing of data from cache to storage device right before power outage occurs but I don't know if it applies also to occasional system crash. This option seem to be complementary to write-back cache reducing or potentially eliminating risk of data loss or corruption of file system. I have questions about relevance of last 2 options to today's modern SSDs in order to get best performance and with less wear on SSDs: I know that traditional hard drives come with onboard cache (I wonder what type of cache that is), but do SSDs also come with cache? Assuming they do, is this cache faster than their NAND flash and system RAM and worth taking the risk of utilizing it by enabling write-back cache? I read somewhere that generally storage device's cache is faster than RAM, but I want to be sure. Additionally I read that write-caching should be enabled since current data that is to be written later to NAND flash is kept for a while in cache and provided there is data that gets modified a lot before finally being written, holding of this data and its periodic release reduces its write times to SSD thereby reducing its wearing. Now regarding to write-cache buffer flushing, I heard that SSD controllers are so fast by themselves that enabling this option is not required, because they manage flushing. However, once again, I don't know if SSDs have their own onboard cache and whether or not it is faster than their NAND flash and system RAM because if it is, keeping this option enabled would make sense. Recently I have posted question about issue with my Intel 330 SSD 120GB which was main reason to do deeper research having suspicion of write-caching policy being the culprit of SSD's freezing issue assuming data being released is what causes freezes. Currently I have write-cache enabled and write-cache buffer flushing disabled because I believe SSD controller's management of write-cache flushing and Windows write-cache buffer flushing are conflicting with each other: Since I want to troubleshoot in small steps to finally determine the source of issue, I have decided to start with write-caching policy and the move to drivers, switching to AHCI later on and finally disabling DIPM (device initiated power management) through registry modification thanks to @TomWijsman

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• need assistance with my.cnf - 1500% CPU usage

  - by Alan Long

  I'm running into a few issues with our new database server. It is a HP G8 with 2 INTEL XEON E5-2650 processors and 32GB of ram. This server is dedicated as a MySQL server (5.1.69) for our intranet portal. I have been having issues with this server staying alive - I notice high CPU usage during certain times of day (8% ~ 1500%+) and see very low memory usage (7 ~ 15%) based on using the 'top' command. When the CPU usage passes 1000%, that is when the app usually dies. I'm trying to see what I'm doing wrong with the config file, hopefully one of the experts can chime in and let me know what they think. See below for my.cnf file: [mysqld] default-storage-engine=InnoDB datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock #user=mysql large-pages # Disabling symbolic-links is recommended to prevent assorted security risks symbolic-links=0 max_connections=275 tmp_table_size=1G key_buffer_size=384M key_buffer=384M thread_cache_size=1024 long_query_time=5 low_priority_updates=1 max_heap_table_size=1G myisam_sort_buffer_size=8M concurrent_insert=2 table_cache=1024 sort_buffer_size=8M read_buffer_size=5M read_rnd_buffer_size=6M join_buffer_size=16M table_definition_cache=6k open_files_limit=8k slow_query_log #skip-name-resolve # Innodb Settings innodb_buffer_pool_size=18G innodb_thread_concurrency=0 innodb_log_file_size=1G innodb_log_buffer_size=16M innodb_flush_log_at_trx_commit=2 innodb_lock_wait_timeout=50 innodb_file_per_table #innodb_buffer_pool_instances=4 #eliminating double buffering innodb_flush_method = O_DIRECT flush_time=86400 innodb_additional_mem_pool_size=40M #innodb_io_capacity = 5000 #innodb_read_io_threads = 64 #innodb_write_io_threads = 64 # increase until threads_created doesnt grow anymore thread_cache=1024 query_cache_type=1 query_cache_limit=4M query_cache_size=256M # Try number of CPU's*2 for thread_concurrency thread_concurrency = 0 wait_timeout = 1800 connect_timeout = 10 interactive_timeout = 60 [mysqldump] max_allowed_packet=32M [mysqld_safe] log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid log-slow-queries=/var/log/mysql/slow-queries.log long_query_time = 1 log-queries-not-using-indexes we connect to one database with 75 tables, the largest table has 1,150,000 entries and the second largest has 128,036 entries. I have also verified that our PHP queries are optimized as best as possible. Reference - MySQLtuner: >> MySQLTuner 1.2.0 - Major Hayden <[email protected]> >> Bug reports, feature requests, and downloads at http://mysqltuner.com/ >> Run with '--help' for additional options and output filtering -------- General Statistics -------------------------------------------------- [--] Skipped version check for MySQLTuner script [OK] Currently running supported MySQL version 5.1.69-log [OK] Operating on 64-bit architecture -------- Storage Engine Statistics ------------------------------------------- [--] Status: -Archive -BDB -Federated +InnoDB -ISAM -NDBCluster [--] Data in InnoDB tables: 420M (Tables: 75) [!!] Total fragmented tables: 75 -------- Security Recommendations ------------------------------------------- [!!] User '[email protected]' has no password set. -------- Performance Metrics ------------------------------------------------- [--] Up for: 1h 14m 50s (8M q [1K qps], 705 conn, TX: 6B, RX: 892M) [--] Reads / Writes: 68% / 32% [--] Total buffers: 19.7G global + 35.2M per thread (275 max threads) [!!] Maximum possible memory usage: 29.1G (93% of installed RAM) [OK] Slow queries: 0% (472/8M) [OK] Highest usage of available connections: 66% (183/275) [OK] Key buffer size / total MyISAM indexes: 384.0M/91.0K [OK] Key buffer hit rate: 100.0% (173 cached / 0 reads) [OK] Query cache efficiency: 96.2% (7M cached / 7M selects) [!!] Query cache prunes per day: 553614 [OK] Sorts requiring temporary tables: 0% (3 temp sorts / 1K sorts) [!!] Temporary tables created on disk: 49% (3K on disk / 7K total) [OK] Thread cache hit rate: 74% (183 created / 705 connections) [OK] Table cache hit rate: 97% (231 open / 238 opened) [OK] Open file limit used: 0% (17/8K) [OK] Table locks acquired immediately: 100% (432K immediate / 432K locks) [OK] InnoDB data size / buffer pool: 420.9M/18.0G -------- Recommendations ----------------------------------------------------- General recommendations: Run OPTIMIZE TABLE to defragment tables for better performance MySQL started within last 24 hours - recommendations may be inaccurate Reduce your overall MySQL memory footprint for system stability Increasing the query_cache size over 128M may reduce performance Temporary table size is already large - reduce result set size Reduce your SELECT DISTINCT queries without LIMIT clauses Variables to adjust: *** MySQL's maximum memory usage is dangerously high *** *** Add RAM before increasing MySQL buffer variables *** query_cache_size (> 256M) [see warning above] Thanks in advanced for your help!

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• SQL SERVER – Activity Monitor and Performance Issue

  - by pinaldave

  We had wonderful SQLAuthority News – Community Tech Days – December 11, 2010 event yesterday. After the event, we had meeting among Jacob Sebastian, Vinod Kumar, Rushabh Mehta and myself. We all were sharing our experience about performance tuning consultations. During the conversation, Jacob has shared wonderful story of his recent observation. The story is very small but the moral of the story is very important. The story is about a client, who had continuously performance issues. Client used Activity Monitor (Read More: SQL SERVER – 2008 – Location of Activity Monitor – Where is SQL Serve Activity Monitor Located) to check the performance issues. The pattern of the performance issues was very much common all the time. Every time, after a while the computer stopped responding. After doing in-depth performance analysis, Jacob realized that client once opened activity monitor never closed it. The same activity monitor itself is very expensive process. The tool, which helped to debug the performance issues, also helped (negatively) to bring down the server. After closing the activity monitor which was open for long time, the server did not have performance issues. Moral of the story: Activity Monitor is great tool but use it with care and close it when not needed. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Best Practices, Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQLAuthority News – Guest Post – FAULT Contract in WCF with Learning Video

  - by pinaldave

  This is guest post by one of my very good friends and .NET MVP, Dhananjay Kumar. The very first impression one gets when they meet him is his politeness. He is an extremely nice person, but has superlative knowledge in .NET and is truly helpful to all of us. Objective: This article will give a basic introduction on: How to handle Exception at service side? How to use Fault contract at Service side? How to handle Service Exception at client side? A Few Points about Exception at Service Exception is technology-specific. Exception should not be shared beyond service boundary. Since Exception is technology-specific, it cannot be propagated to other clients. Exception is of many types. CLR Exception Windows32 Exception Runtime Exception at service C++ Exception Exception is very much native to the technology in which service is made. Exception must be converted from technology-specific information to natural information that can be communicated to the client. SOAP Fault FaultException<T> Service should throw FaultException<T>, instead of the usual CLR exception. FaultException<T> is a specialization of Fault Exception. Any client that programs against FaultException can handle the Exception thrown by FaultException<T>. The type parameter T conveys the error detail. T can be of any type like Exception, CLR Type or any type that can be serialized. T can be of type Data contract. T is a generic parameter that conveys the error details. You can read complete article http://dhananjaykumar.net/2010/05/23/fault-contract-in-wcf-with-learning-video/ Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority News, T SQL, Technology

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• SQL SERVER – T-SQL Constructs – *= and += – SQL in Sixty Seconds #009 – Video

  - by pinaldave

  There were plenty of request for Vinod Kumar to come back with SQL in Sixty Seconds with T-SQL constructs after his very first well received construct video T-SQL Constructs – Declaration and Initialization – SQL in Sixty Seconds #003 – Video. Vinod finally comes up with this new episode where he demonstrates how dot net developer can write familiar syntax using T-SQL constructs. T-SQL has many enhancements which are less explored. In this quick video we learn how T-SQL Constructions works. We will explore Declaration and Initialization of T-SQL Constructions. We can indeed improve our efficiency using this kind of simple tricks. I strongly suggest that all of us should keep this kind of tricks in our toolbox. More on Errors: Declare and Assign Variable in Single Statement Declare Multiple Variables in One Statement I encourage you to submit your ideas for SQL in Sixty Seconds. We will try to accommodate as many as we can. If we like your idea we promise to share with you educational material. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Database, Pinal Dave, PostADay, SQL, SQL Authority, SQL in Sixty Seconds, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Video

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